• bashy
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Topic: Low cut 24dB = 11dB

Have found the low cut filters do not cut as much as they are labelled on the UFX II using previous and latest firmware v23.

± 0.1 dB depending on cutoff frequency, rounded up to the nearest decibel:

24dB = 11db
18dB = 10dB
12dB = 9dB
6db = 7dB

Discovered this measuring speakers using room eq wizard, but same results when running a test tone at half the frequency of the low cut frequency through the analogue ins or via loopback and checking the level in totalmix / digicheck.

Also, the eq graph in totalmix reflects this, for example lining up the 24dB low cut to the bottom left edge at 20Hz -20dB is 64Hz. Whereas 64Hz should be down -24dB at 32Hz.

2 Reply by MC

  • MC
  • MC
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  • Registered: 2007-04-06
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Re: Low cut 24dB = 11dB

The low cut works as expected and won't change, sorry. For performance reasons it uses a Q factor of 0.5, which is why the transition seems less steep than seen in other places (Q 0.7).

Regards
Matthias Carstens
RME

MC's Website

  • bashy
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Re: Low cut 24dB = 11dB

Seems a little arbitrary, that the 24dB filter isn’t attenuating the signal by 24dB per octave.

So it is in fact a 48dB filter*

*Q0.25

Who knew?!